I can't speak for the R09's mics. personally, but I have a friend who owns one (not the 09HR model) and I believe his recordings have sound decent with the internals only. However, I can understand you wanted to look at something else as there is newer gear out there that might have better battery life and recording modes than the R09.
My work horse is the Sony PCM M10 (discontinued). Internal mics on the M10 are good, but I don't think they are as good as the R09HR that I also at one point owned. I can't speak much about the Edirol R05 model, as I never owned one and don't know anyone who has recorded internal mics with it only - but I assume it might be comparable to the R09HR. I can't imagine the quality being subpar.
I also own a Olympus LS-P2 as a backup. Not a bad recorder for being small and stealth looking and battery life seems decent for being one AAA battery. Haven't used the internal mics to test them out just yet, but it uses a three microphone system apparently. Was not too impressed with the way it handles my battery box and mics at certain shows. Seemed a little too bassy for my liking. I believe that shouldn't be the case, as I use the same external gear combo on the Sony and it works perfectly. However, it is a different recorder and different brand.
To answer your question - if you are looking for something else, maybe a R05 might be a better option if you don't mind the design of it and not being as compact as the Olympus LS-P2. I would recommend the Sony PCM M10 if you plan on getting a battery box and external mics because the mics aren't as good. If you stealth with the PCM M10, you still got plenty of options on how you can make that happen with that recorder with external gear. Not everything has to be big and bulky to make it sound great (in my opinion). I have already wrote a post previously about what I think is a good enough setup with the M10 when responding about the Roland CS 10EM mics in the mics section, that I've owned for years now and still use.